Fig. 7From: Voltage-Polarity Dependent Programming Behaviors of Amorphous In–Ga–Zn–O Thin-Film Transistor Memory with an Atomic-Layer-Deposited ZnO Charge Trapping LayerHigh-resolution O1s XPS spectra of the as-deposited ZnO film and those annealed at 250 °C in O2 and N2, respectively. O1 and O2 correspond to O2− ions bound with Zn2+ and oxygen vacancies, respectively. O3 is attributed to chemisorbed oxygen element (–OH, etc). To remove unintentionally surface contaminants, all the samples were etched with in situ Ar ion bombardmentBack to article page